PICV Installation for Chiller pipe

[Wayne _ Lunar]

Hi experts,


I’m currently working on an MEP project involving a chiller system with 169 FCUs and AHUs, divided into 14 branches. At the moment, only balancing valves are installed at the return pipe of each FCU/AHU, but there are no balancing valves at the branch level. This makes water balancing very difficult and time-consuming.


To improve this, I’m considering installing PICVs (Pressure Independent Control Valves) at each of the 14 branches to simplify and speed up the balancing process.


Do you think this is a good solution? Also, should a strainer be installed upstream of each PICV?


Thank you in advance!

 

[LittleInch]

I would invest in a clamp on meter if I was you.

Branch flow control might make life easier, but you're still stuck with balancing a branch. How does each FCU / AHU control temperature? by air flow or water flow?

 

[HVAC-Novice]

Assuming you mean each branch could lead to multiple AHU/FCU, those added balancing valves would be a waste and just add pressure drop.

How is the pump controlled? Are you not using a VFD and pressure sensors?

And a PICV is a Pressure Independent Control Valve. Why would you need control valves at branches? Install PICV at each AHU/FCU and remove those balancing valves. No balancing needed. You just need to verify flow (some PICV include a flow meter to do that) and use valve position to determine the pump pressure setpoints.

Manual balancing valves are way out of date. and they should be set iteratively. No balancer actually does that (and most wouldn't understand it).

 

[LittleInch]

To be fair I can see that with one branch set at what ever flow say ten units should flow at then jumping around 10 units to balance them know you have a fixed flow in from the branch might be a bit easier than an unknown impact from one unit on 168 other units.

one per unit is definitely the best.